1. Field of the Invention
The present invention relates to an apparatus and method for Automatic Repeat reQuest (ARQ) in a wireless communication system. More particularly, the present invention relates to an apparatus and method for ARQ feedback polling to a receive end in a transmit end of a wireless communication system.
2. Description of the Related Art
Wireless communication systems can suffer from the occurrence of errors of transmitted/received data according to channel states of radio resources. However, the wireless communication systems can control or recover the errors of the data using an ARQ technique to enhance transmission reliability.
In a case of the use of an ARQ technique, a receive end informs a transmit end of success or failure of reception of data from the transmit end. For example, in a case where errors do not occur in data received from a transmit end, a receive end transmits ACKnowledgement (ACK) information to the transmit end. On the other hand, in a case where errors occur in data received from the transmit end, the receive end transmits Negative ACKnowledgement (NACK) information to the transmit end. Here, a series of operations in which the receive end transmits success or failure of reception of data to the transmit end is called ARQ feedback.
Depending on ARQ feedback information received from a receive end, a transmit end can determine success or failure of transmission of data to the receive end. If receiving ACK information from the receive end, the transmit end shall transmit new data to the receive end. On the other hand, if receiving NACK information from the receive end, the transmit end shall retransmit data associated with the NACK information to the receive end.
If a lifetime of data expires, a transmit end shall delete the data from a buffer. Also, the transmit end cannot be aware of any time point when a receive end will transmit ARQ feedback information. Thus, in a case where the transmit end fails to receive ARQ feedback information before a lifetime of data expires, there is a problem in which the transmit end should delete corresponding data in a state of lack of knowledge about a reception state of data.
Therefore, a need exists for an apparatus and method for ARQ feedback polling in a wireless communication system for recognizing a time point when ARQ feedback information is received from a receive end.